A photodiode includes a p-type ohmic contact and a p-type substrate in contact with the p-type ohmic contact. An intrinsic layer is formed over the substrate and including a III-V material. A transparent II-VI n-type layer is formed on the intrinsic layer and functions as an emitter and an n-type ohmic contact.

An engineered substrate comprises: a seed layer made of a first semiconductor material for growth of a solar cell; a support substrate comprising a base and a surface layer epitaxially grown on a first side of the base, the base and the surface layer made of a second semiconductor material; a direct bonding interface between the seed layer and the surface layer; wherein a doping concentration of the surface layer is higher than a predetermined value such that the electrical resistivity at the direct bonding interface is below 10 mOhm.Math.cm.sup.2, preferably below 1 mOhm.Math.cm.sup.2; and wherein a doping concentration of the base as well as the thickness of the engineered substrate are such that absorption of the engineered substrate is less than 20%, preferably less than 10%, and total area-normalized series resistance of the engineered substrate is less than 10 mOhm.Math.cm.sup.2, preferably less than 1 mOhm.Math.cm.sup.2.

The present invention refers to a photovoltaic cell (1) comprising a heterojunction with a base layer (L4, L4′, L4″) made from an Aluminium-Ar-senic-basedalloy and an emitter layer (L3, L3′) made from an Indium-Phosphorous based alloy wherein the emitter layer (L3, L3′) has a thickness smaller than 100 nm and acts as a passivation layer to prevent oxidation of the base layer and reduces surface recombination (L4, L4′, L4″).

A preparation method of the light absorption layer of a copper-indium-gallium-sulfur-selenium film solar cell is provided. The method employs a non-vacuum liquid-phase chemical technique, which comprises following steps: forming source solution containing copper, indium, gallium, sulfur and selenium; using the solution to form a precursor film on a substrate by a non-vacuum liquid-phase process; drying and annealing the precursor film. Thus, a compound film of copper-indium-gallium-sulfur-selenium is gained.

A multijunction solar cell assembly and its method of manufacture including interconnected first and second discrete semiconductor body subassemblies disposed adjacent and parallel to each other, each semiconductor body subassembly including first top subcell, second (and possibly third) lattice matched middle subcells; a graded interlayer adjacent to the last middle solar subcell; and a bottom solar subcell adjacent to said graded interlayer being lattice mismatched with respect to the last middle solar subcell; wherein the interconnected subassemblies form at least a four junction solar cell by a series connection being formed between the bottom solar subcell in the first semiconductor body and the bottom solar subcell in the second semiconductor body.

A photodetector comprising a photoabsorber, comprising a doped semiconductor, a contact layer comprising a doped semiconductor and a barrier layer comprising a charge carrier compensated semiconductor, the barrier layer compensated by doping impurities such that it exhibits a valence band energy level substantially equal to the valence band energy level of the photo absorbing layer and a conduction band energy level exhibiting a significant band gap in relation to the conduction band of the photo absorbing layer, the barrier layer disposed between the photoabsorber and contact layers. The relationship between the photo absorbing layer and contact layer valence and conduction band energies and the barrier layer conduction and valance band energies is selected to facilitate minority carrier current flow while inhibiting majority carrier current flow between the contact and photo absorbing layers.

Provided are a semiconductor device and an optical sensor device, each having reduced dark current, and detectivity extended toward longer wavelengths in the near-infrared. Further, a method for manufacturing the semiconductor device is provided. The semiconductor device 50 includes an absorption layer 3 of a type II (GaAsSb/InGaAs) MQW structure located on an InP substrate 1, and an InP contact layer 5 located on the MQW structure. In the MQW structure, a composition x (%) of GaAsSb is not smaller than 44%, a thickness z (nm) thereof is not smaller than 3 nm, and z≥−0.4x+24.6 is satisfied.

Thin freestanding nitride veneers can be used for the fabrication of semiconductor devices. These veneers are typically less than 100 microns thick. The use of thin veneers also eliminates the need for subsequent wafer thinning for improved thermal performance and 3D packaging.

An infrared photodetector including a substrate, a barrier layer, and an absorber layer disposed between the substrate and the barrier layer, the absorber layer having a molar concentration grading that results in an uncoated quantum efficiency of greater than about 40 percent.

A system includes a pixel having a diffusion layer within a cap layer. The diffusion layer defines a front side and an illumination side opposite the front side with an absorption layer operatively connected to the illumination side as well as the diffusion and cap layers. A set of alternating oxide and nitride layers are deposited on the front side of the cap and diffusion layers.